Organogold compounds

ABSTRACT

THERE IS PROVIDED NOVEL ORGANOLGOLD COMPOUNDS HAVING THE FOURMULA RNCAUR1 WHERE R IS AN ALKYL GROUP CONTAINING UP TO 12 CARBON ATOMS OR AN ARYL GROUP CONTAINING UP TO 12 CARBON ATOMS IN THE RING SYSTEM WHERE R1 IS AN ALKYL GROUP CONTAINING UP TO 12 CARBON ATOMS, AN ARYL GROUP CONTAINING UP TO 12 CARBON ATOMS IN THE RING SYSTEM OR A HETEROCYCLIC 5-OR 6-MEMBERED RING CONTAINING O, S OR N IN THE RING, AND AU IS GOLD IN THE + 1 OXIDATION STATE. THESE COMPOUNDS ARE USEFUL IN THE PRODUCTION OF GOLD FILMS.

United States Patent O 3,657,296 ORGANOGOLD COMPOUNDS Lawrence G. Vaughan, Wilmington, Del., assiguor to 11% du Pont de Nemours and Company, Wilmington,

No Drawing. Filed July 30, 1970, Ser. No. 59,713

' Int. Cl. .C07f 1/12 US. Cl. 260-430 1 11 Claims ABSTRACT OF THE DISCLOSURE There is provided novel organogold compounds having the formula RNCAuR where R is an alkyl group containing up to 12 carbon atoms or an aryl group containing up to 12 carbon atoms in the ring system where R is an alkyl group containing up to 12 carbon atoms, an aryl group containing up to 12 carbon atoms in the ring system or a heterocyclic or 6-membered ring containing 0, S or N in the ring, and Au is gold in the +1 oxidation state. These compounds are useful in the production of gold films.

BACKGROUND OF THE INVENTION In producing metallic gold films on substrates, for decorative purposes or for printed electrical circuitry, a composition containingan organogold compound is applied, in the desired pattern or configuration, to the-substrate and heated to decompose the compound and volatilize the organic constituents leaving a metallic gold film adhering to the substrate. The gold compounds principally used for this purpose have been gold resinates which possess certain disadvantages, chiefly odor and lack of purity.

It is the principal object of the present invention to provide novel organogold compounds which lack odor and can be obtained in a high state ofi purity and which are also highly soluble in organic solvents and decompose at relatively low temperature thereby being particularly useful in the productionof metallicagold films.

SUMMARY OF THE INVENTION The novel compounds of the present invention have the Formula RNCAuR where R is an alkyl group containing up to 12 carbon atoms or an aryl group containing up to 12 carbon atoms in the ring system; where R is an alkyl group containingup to 12 carbon atoms, an aryl group containing up to 12 carbon atoms in the ring system or a heterocyclic 5- or 6-membered ring containing 0, S or N in the ring, and where Au is gold in the +1 oxidation state.

DETAILED DESCRIPTION OF THE INVENTION The compounds of the invention may readily be prepared by reacting a chloro(organisocyanide)gold(l) complex, RNCAuCl, with a Grignard reagent, R MgBr, according to the equation RNCAuCl +R MgBr- RNCAuR MgBrCl As will be seen from the foregoing, the reaction involves 1 mol of the chloro(organoisocyanide)gold(I) complex .per mol of Grignard compound. However, in practice it is preferred to use some excess of the less expensive Grignard compound, generally not over 25% excess, to force the reaction to completion.

In the products of the invention R is derived from the R of the chloro(organoisocyanide)gold(I) compound, and hence R in the latter compound will be alkyl containing up to 12 carbon atoms or aryl containing up to 12 carbon atoms in the ring system. The term alkyl includes cycloalkyl, and examples of alkyl R in the chloro(alkylisocyanide)gold(I) compound, and hence in the products 3,657,296 Patented Apr. 18, 1972 of the invention, are: methyl, ethyl, t-butyl, n-hexyl, 2- ethylhexyl, dodecyl, cyclopentyl and cyclohexyl. R may be aryl, such as phenyl, biphenyl or naphthyl and the aryl nucleus may contain substituents such as up to five alkyl groups, each containing up to 6 carbon atoms, or up to 4 halogens. Examples of aryl R in the chloro(arylisocyanide)gold(I) compounds, and hence in the products of the invention, are: phenyl, m-fluorophenyl, p-fiuorophenyl, p-iodophenyl, p-tolyl, 2,6-diethylphenyl, 2,6-diisopropylphenyl, 2-methyl-6-ethyl phenyl, 2,6 di-n-hexyl phenyl, 2,3,4,5,6-pentamethyl phenyl, biphenyl, 4-methylbiphenyl, naphthyl and Z-methyl-l naphthyl. Particularly preferred Rgroups are dialkyl phenyl groups, each alkyl group containing up to 6 carbon atoms, especially where the alkyl groups are in the 2 and 6 positions.

The chloro(organoisocyanide)gold(I) compounds may be prepared by reacting the appropriate organoisocyanide with chloro(dimethylsulfide)gold(I) as disclosed and claimed in my copending application Ser. No. 59,712 filed July 30, 1970 [See also J. Am. Chem, Soc., 91, 6151 (1969)].

R in the products of the invention, is derived from the Grignard compound R MgBr. Hence, R in the Grignard compound may be alkyl containing up to 12 carbon atoms, aryl containing up to 12 carbon atoms, in the ring system or a heterocyclic 5- or 6-membered ring containing an O, S or N in the ring. The term alkyl includes cycloalkyl, and examples of alkyl R in the Grignard compound, and hence in the products of the invention are: methyl, ethyl, t-butyl, 2-ethylhexyl, dodecyl, cyclopentyl and cyclohexyl. -R may be aryl, such as phenyl, biphenyl or naphthyl and the aryl nucleus may contain substituents such as up to five alkyl groups, each containing up to 6 carbon atoms, or up to five halogens. Examples of aryl R in the Grignard compound, and hence in the products of the invention, are: phenyl, m-fiuorophenyl, p-fiuorophenyl, ptolyl, ethylphenyl, p-t-butylphenyl, p-n-hexylphenyl, 2,6- diethylphenyl, 2,6-diisopropylphenyl, Z-methyl -6-ethyl phenyl, 2,6-di-n-hexylphenyl, 2,3,4,5,6-pentamethyl phenyl, biphenyl, 4'-methylbis phenyl, naphthyl and Z-methyl-lnaphthyl. Examples of R as a 5-'or 6-membered ring containing an O, S or N in the ring are: Z-thienyl, 2-furyl, 3-isothiazolyl and 2-(6-methyl)pyridyl. Particularly preferred R groups are alkylphenyl groups in which the alkyl group contains up to 6 carbon atoms.

In preparing the products of the invention, the chloro (organoisocyanide)gold(I) compound and the Grignard compound are reacted in an organic solvent. The preferred solvents are ethers, like diethylether and tetrahydrofuran. The concentration of the reactants in the solvent is not critical and may range, in terms of the chloro (organoisocyanide)gold(I) compound, from about 0.05 to about 2 molar and, in most cases, from about 0.1 to about 1 molar, including any undissolved initially. In this connection, any of the reactant that does not dissolve initially will eventually become dissolved'and reacted as the reaction proceeds.

The reaction temperature is not especially critical and may range from 0 to about 100 C. or to reflux depending upon the solvent. Generally, a slight heating is preferred and the preferred temperature range is from about 30 to about C.

Because of the sensitivity of the Grignard compound to air and moisture it is advisable to protect it, as by carry,- ing out the reaction under an atmosphere of inert gas like nitrogen or argon.

The reaction product may be recovered from the reaction medium by the addition of water to precipitate the magnesium salts, separating the organic layer and removing the organic solvent by heating or under reduced pressure, or both. The product may be purified using conventional techniques, such as by recrystallization.

Organo lithium compounds R Li where R is as defined above, are generally equivalent to the Grignard compounds and may be used in place thereof in producing products of the invention.

-In utilizing the compounds of the present invention to produce gold films, they may be dissolved in a suitable organic solvent. Solvents may be selected from chlorinated hydrocarbons, like chloroform; ketones, like acetone; ethers, like tetrahydrofuran, and the like depending upon the particular compound and its solubility and the concentration desired. Although it is often preferred to have a relatively high concentration of the gold compound in the compositions, particularly where a heavy or thick gold film is desired, much lower concentrations may be dictated when light or thin films are desired. Thus, the concentration of the compound in the composition (in terms of gold present) may range from as low as 0.1 to as high as about 50%, by weight, of gold. In such compositions there may also be included an agent to adjust the viscosity of the composition and/or to aid in film formation. Sulfurized damar gum serves both of these purposes. Also included in the composition may be a flux to promote adhesion of the metallic gold to the substrate. Resinates of metals like chromium, rhodium and bismuth, and combinations thereof, are suitable for this purpose.

The invention will be more readily understood from a consideration of the following specific examples which are given for purposes of illustration only and are not intended to limit the scope of the invention in any way.

EXAMPLE 1 Preparation of 4-t-butylphenyl(2,6-diethylphenylisocyanide) gold (I) CzH5 To a solution of the Grignard reagent (32.5 mmoles) in tetrahydrofuran at 0 C. was added dropwise a solution of 10.0 g. (25.6 mmoles) of the gold complex in 30 ml. tetrahydrofuran. The mixture was stirred at room temperature for one hour, then heated at 60 C. for thirty minutes. After hydrolysis with saturated aqueous ammonium chlo ride solution, the organic layer was filtered and dried over sodium sulfate. The solvent was then removed under reduced pressure and the solid residue recrystallized from cyclohexane. The yield of product, M.P. l67-170 C. dec., was 8.42 g. (67% Analysis.-Calcd. for C H AuN (percent): C, 51.53; H, 5.36; Au, 40.25; N, 2.86. Found (percent): C, 50.88; H, 5.21; Au, 40.01; N, 2.83.

EXAMPLE 2 Preparation of m-fiuorophenyl(m-fiuorophenylisocyanide) gold(I) Q-Mgllr @nozmor l I F F A solution of the m-fiuorophenylmagnesium bromide (14.3 mmoles) was prepared in 50 ml. of ether. The solution was cooled to 0 C. and 4.5 g. (12.8 mmoles) of chloro(m fluorophenylisocyanide)gold(I) was added in one batch. The mixture was allowed to warm, stirred at room temperature for 1 hour and then refluxed for 1 hour. After hydrolysis with excess water, the ether layer was separated, dried over sodium sulfate, treated with decolorizing charcoal and filtered. The ether was removed under reduced pressure. The product was recrystallized first from a mixture of 200 ml. of cyclohexane and 10 ml. of benzene (held at 65 C.) then recrystallized a second time from methanol (maximum temperature 60 C.), giving an analytical product of M.P. -l1l C., dec. The yield was 4.95 g. (94%).

Analysis.Calcd. for C H AuF N (percent): C, 37.78; H, 1.95; Au, 47.68; F, 9.20; -N, 3.39. Found (percent): C, 37.73; H, 1.80; Au, 47.51; F, 9.10; N, 3.24.

EXAMPLES 3-5 Following the procedure of Example 2 but using p-fluorophenylmagnesium bromide and chloro(p-fiuorophenylisocyanide)gold(I); p-fluorophenylmagnesium bromide and chloro(m-fluorophenylisocyanide)gold(I), and m-fluorophenylmagnesium bromide and chloro(p-fiuorophenylisocyanide)gold(l), respectively, the following respective compounds were prepared.

Ex.: Compounds 3 p-fluorophenyl(p-fiuorophenylisocyanide)gold(I). 4 p-fluorophenyl(m-fluorophenylisocyanide)gold (I). 5 m-fluorophenyl (p-fluorophenylisocyanide gold ('I) In preparing compounds of Examples 3 and 4, they were recrystallized first from a mixture (3:1 and 5: 1, respectively) of cyclohexane and benzene, then from methanol. The compound of Example 5 was recrystallized first from cyclohexane, then from ethanol.

Analysis.Calculated for C H AuF N (percent): C, 37.78; H, 1.95; Au, 47.68; F, 9.20; N, 3.39.

row-co zouq By following procedures analogous to those set forth in the foregoing examples there may be prepared other organo gold compounds of the invention illustrated by the following compounds: methyl (n-hexylisocyanide) gold(I); t-butyl(p-tolylisocyanide)gold(I); o-ethylphenyL (n-dodecylisocyanide)gold(I); 2 thienyl(t butylisocyanide)gold(I), and 2 furyl(2,6-diisopropylphenylisocyanide)gold(I), and 4-biphenyl(2-naphthylisocyanide) gold (I).

The following examples illustrate the utility of the compounds of the present invention.

EXAMPLE 6 One gram of the 4-t-butylphenyl(2,6-diethylphenylisocyanide) gold(I) of Example 1, 0.3 g. of sulfurized damar gum and 0.35 g. of a 4.5% solution of a mixed chromium-, rhodium-, bismuth resinate(0.4 chromium resinate, 0.9 rhodium resinate and 3.1 bismuth resinate) in a vehicle composed of 30% o-nitrotoluene, 25% cineol, 20% chlorobenzene, 15% camphor and 10% spike lavender oil, were mixed with 3 g. of chlorobenzene.

The mixture was brushed onto a china plate and fired to 750 C. The resulting bright gold film had excellent abra- SlOll resistance.

In a similar manner compositions may be prepared and used employing the compounds of Examples 2-5 and tetrahydrofuran, acetone or chloroform as principal solvent in place of the chlorobenzene used above.

What is claimed is:

1. Gold compounds of the formula RNCAuR where R is selected from the group consisting of alkyl groups containing up to 12 carbon atoms, and aryl groups containing up to 12 carbon atoms in the ring system; R is selected from the group consisting of alkyl groups containing up to 12 carbon atoms, aryl groups containing up to 12 carbon atoms in the ring system and heterocyclic 5- or 6-membered rings containing 0, S or N in the ring, and Au is gold in the +1 oxidation state.

2. The compounds of claim 1 where R is a phenyl group.

3. The compounds of claim 2 wherein R is a dialkyl phenyl group, each alkyl group containing from 1 to 6 carbon atoms.

4. The compound of claim 3 wherein the alkyl groups are in the 2- and 6-positions.

5. The compounds of claim 4 wherein R is 2,6-diethylphenyl.

6. The compounds of claim 1 wherein R is an alkylphenyl group, the alkyl group containing from 1 to 6 carbon atoms.

7. The compounds of claim 2 wherein R is an alkyl phenyl group, the alkyl group containing from 1 to 6 carbon atoms.

8. The compounds of claim 3 wherein R is an a1kylphenyl group, the alkyl group containing from 1 to 6 carbon atoms.

9. The compounds of claim 4 wherein R is an alkylphenyl group, the alkyl group containing from 1 to 6 carbon atoms.

10. The compounds of claim 5 wherein R is an alkylphenyl group, the alkyl group containing from 1 to 6 carbon atoms.

11. 4 t butylphenyl(2,6 diethylphenylisocyanide) gold(I).

References Cited Vaughan et al., J. Amer. Chem. Soc., vol. 91, pp. 6151-6 (October 1969).

TOBIAS E. LEVOW, Primary Examiner H. M. S. SNEED, Assistant Examiner US. Cl. X.R. 

